Flat-Rate Design Method for Low- and Medium-Rise Reinforced Concrete Structures

Abstract

A simplified procedure to proportion earthquake-resistant reinforced concrete structures without irregularities is presented. The flatrate method may also be used to assess the vulnerability of existing structures to earthquakes in a simple manner. The method is based on the concept that the maximum expected roof drift of a building is proportional to the ratio of total mass to stiffness of the lateral load resisting system. This method is not intended to provide sharp details about the expected performance of buildings but to evaluate the overall earthquake resistance of building configurations in a simple manner. For this reason, it is intended for the evaluation or design of low- and medium-rise reinforced concrete structures. A number of design examples were completed with various performance objectives and included buildings with two and five stories and lateral load resisting systems with moment resisting frames and structural walls. For the performance objectives defined in the study, the use of structural walls was more cost-effective than moment resisting frames.